I hadn't heard of this jacket before but I think those here will like it. It's primaloft one and pertex quantum with zip off sleeves. It's on sale for $100 right now at REI, both online and in stores. It reminds me a LOT of my thermawrap, and I'd have bought one if I didn't already have the thermawrap. It's a few ounces heavier, but still very light. The medium fit me well whereas I wear a large thermawrap.